1. Technical Field
The present invention is in the field of fasteners such as threaded bolts and nuts used with sheet materials such as metal and the like. Particularly, the present invention relates to a sealing washer assembly including a threaded fastener and a resilient member oversized with respect to the threaded fastener. More particularly, the present invention relates to an assembly for attaching one member to another member, via an opening in the first member and then sealing the attachment against the passage of fluid, including but not limited to air, and for preventing noise transmission through the connection.
2. Discussion
A nut and bolt combination is a well known device for securely fastening two or more members. Generally speaking, a metal washer encircles the bolt shaft and is interposed between the nut and the member against which the nut is tightened. Location of a washer between rotatable and static members is known to promote a fit of the fastened members which is more resistant to loosening from vibration. The nuts, bolts and washers in common use are often manufactured of metal but modification of this arrangement has been suggested for various purposes over the years.
For example, U.S. Pat. No. 2,982,573 to McKee, Jr. describes a composite sealing washer having an annular sealing portion constructed of neoprene rubber that is received within a cup-shaped flexible metal member. A washer is used in conjunction with a conventional nut and bolt to fasten two plates together. The annular sealing portion is oversized so that when the nut is tightened onto the bolt, the material of the sealing portion spreads into a gap between the bolt and plates. It is also known to secure a rubber gasket or other suitable flexible material to a washer with adhesive for sealing the aperture through which a fastener passes, for example, when sealing an opening in an automotive vehicle. The gasket is positioned to be compressed between the washer and the workpiece.
One longstanding problem with known sealing washers arises when the gasket is compressed between the clamped components of the formed joint and subsequently relaxes, leading to leakage. Although sealing washers are generally considered low-cost items in themselves, they can be very time consuming to replace in the event of failure.
Another problem with known assemblies is that, due to the compression of the gasket and the virtual metal contact effectual, noise can be transmitted through the assembly from the attached member into the other member.